Law360, New York (February 25, 2015, 10:39 AM EST) -- In Teva Pharm. USA Inc. v. Sandoz Inc., 574 U.S. ___, 135 S. Ct. 831 (2015), the U.S. Supreme Court held that the Federal Circuit must apply a "clear error" standard of review to factual determinations underlying a claim construction ruling.[1] Under this decision, the Federal Circuit may no longer simply apply a de novo review of a trial court's claim construction analysis without regard to whether that ruling rested in whole or in part on subsidiary factual findings.[2] Litigants and district court judges alike may now consider how to fashion rulings that potentially might limit the effect of de novo review of the ultimate claim construction issue through deference to subsidiary fact finding. The dissent in Teva goes so far as to raise the possibility that appellate review of claim construction may be constrained "any time a district court's claim construction turns on subsidiary evidentiary disputes."[3] It is not clear, however, to what extent the Federal Circuit's implementation of Teva will, in practice, affect the outcome in claim construction appeals....